pH-sensitive nanocontainers

Water-soluble polyelectrolyte nanocapsules can be synthesized by vesicular or emulsion polymerization via core-shell latexes. These particles show a r eversible pH- and ionic strength-dependent swelling transition causing a co nsiderable increase (decrease) of their radius. During this transition gate d pores are opened (closed) in spherical polymer shells, which enable free molecular exchange between the interior of the hollow sphere and the bulk m edium. This pH-switchable control of the permeability of the polyelectrolyt e envelopes can be used to trigger the release of encapsulated materials fr om their central cavity.